Trucks, truck trailers and large shipping or cargo containers are generally of the type having a rectangular configuration with two parallel longitudinal side walls and two end walls. One of the end walls typically includes pivoted double doors to facilitate loading and unloading of the truck trailer compartment. While this type of door is capable of facilitating loading operations, the opening it provides is limited in size to the dimensions of the end wall, and thus is inconvenient for loading certain types of cargo.
Special cargo, or special delivery cargo, also require a greater degree of access to the interior than can be provided by pivoted double doors located on the smaller end wall of the truck trailer. Large heavy cargo, for example, may be difficult to load into the truck trailer via the end wall opening. Where delivery of the cargo is required to be made directly to a construction site or other location where the cargo will be used directly, loading equipment and/or personnel may be sufficiently limited as to make the unloading operation quite difficult. Unloading of bulky cargo from an end wall opening can be difficult even where experienced personnel are available at a designated loading dock with proper equipment, such as a warehouse of other storage facility.
In the past, systems which have been used to provide interior container access via the longitudinal side walls instead of the one end wall, have made use of pivoted single and double doors, as well as doors comprising a flexible curtain. Curtain doors or "curtainside" access systems of the past have consisted of longitudinally as well as vertically moving curtains. While curtainside systems have had the advantage of providing extensive load access to the truck trailer interior, one disadvantage has been inadequate hardware to support and guide the curtains and inadequate security techniques for securing the curtains in a closed position. Another problem with these types of curtainside systems is that they often require the curtain to extend the entire length of the truck trailer.